1. Field of the Invention
The present invention relates to a walking assistance device which reduces a load acting on a leg or legs of a user thereby to assist walking of the user.
2. Description of the Related Art
Hitherto, as this type of walking assistance device, there has been known one equipped with a load transmitting assembly, foot-mounted assemblies to be attached to the feet of a user, and leg links between the load transmitting assembly and the foot-mounted assemblies. The walking assistance device is adapted to transmit forces from the leg links to the body trunk of the user through the intermediary of the load transmitting assembly, thereby permitting a reduction in load acting on the legs of the user (refer to, for example, Japanese Patent Application Laid-Open No. 2007-20909).
In this walking assistance device, each of the leg links includes an upper first link member connected to the load transmitting assembly through the intermediary of a first joint, a lower second link member connected to the foot-mounted assembly through the intermediary of a second joint, and an intermediate third joint assembly which bendably connects the first link member and the second link member. A torque in a stretching direction, i.e., in a direction for reducing the bending angle between the first and the second link members, is imparted to the third joint assembly by a drive source, to generate an assisting force in each of the leg links to support a part of the weight of the user.
Here, laterally offsetting the second link member with respect to the first link member leads to an increased breadth of the entire leg link, causing the leg link to easily come in contact with a leg of the user. For this reason, the first link member and the second link member are desirably connected without the lateral offsetting.
This, however, would inconveniently restrict the maximum bending angle at the third joint assembly to a relatively small angle due to the mutual interference between the first link member and the second link member in the vicinity of the third joint assembly, thus preventing the user from squatting deeply.